[quote=@Double Capybara]
Are planes bound to physics? 

For example, my dreamrealm can be composed of things that would not work on the real world? 
[/quote]

Nop, planes are not bound.

Think of the 'universe' as a bubble, planes of existence are smaller bubbles on the outside, they can't be as bug as the universe, but they are their own separate dimensions with their own laws. For instance, Vowzra may be able to create a dimension where Time passes at completely diffrent rates from the universe